This invention relates to the field of particulate treatment of manufactured parts. More specifically, it relates to devices for the surface treatment of parts to clean, abrade, finish or otherwise prepare the parts for their intended use. Usually such treatment devices employ an abrasive such as sand, steel shot, grit or other materials projected against the parts to be treated at velocities sufficient for the purpose intended. Thus, for example, cast parts can be deburred, peened or cleaned.
Typically, the treatment operations will be accomplished by use of an airless centrifugal blasting wheel which will project the particulate against the parts to be treated. In such an operation it is usually necessary, for the protection of personnel and for efficiency, to conduct the treating operations in a closed blast cabinet or chamber, thereby facilitating recovery and reuse of the abrasive, and protecting personnel from injury by the particulate blast. When a blast chamber is utilized, it becomes necessary to operate in a batch fashion such that a number of parts are placed into a blast chamber, the blasting operation proceeds, and then the blast chamber is emptied of the treated parts and a new batch of parts is placed in it for additional treatment.
A desirable mode of operation would provide for a continuous flow of work into and out of the blast chamber without interrupting the abrasive tight integrity of the chamber. The prior art has disclosed the use of an overhead conveyor system for carrying parts through a blast area. Blast cabinets incorporating the monorail conveyor system have employed multiple flexible curtains or mechanical hinged doors in the work passage openings. These have not been completely effective or have required a disproportionate amount of space to provide complete continuous closure. These closures are often in intimate contact with the workload resulting in rapid failure of the closure parts from wear or from elevated temperatures of the work parts. The mechanical hinged multiple door arrangements require a large number of electrical and pneumatic components for correct synchronous operation and are subject to rapid failure because of their complexity and because of abrasive fouling of the multiple points of relative movement.
The prior art also has disclosed the use of a rotary vestibule to seal a blast chamber, while at the same time providing for ingress and egress of work. In such designs the work has been suspended from hangers permanently attached to the rotating vestibule. Exposed externally from the blast cabinet are one or at the most two hangers which can be loaded and unloaded.
It is accordingly an object of the present invention to provide a blast treatment device which has the following advantages:
Unlimited number of loading and/or unloading locations;
PERMITS LOCATING LOADING AND UNLOADING STATIONS ADJACENT TO POINTS OF PRIOR AND FOLLOWING OPERATIONS TO MINIMIZE MULTIPLE HANDLING OF WORK;
PERMITS LOADING AND UNLOADING TO BE REMOTE FROM INHERENT NOISE OF BLAST OPERATION;
PERMITS LOADING AND UNLOADING REMOTE FROM EXPOSURE TO RANDOM ESCAPING SHOT AND DUST;
PERMITS LOADING AND UNLOADING REMOTE FROM AREAS OF RELATIVE MOTION OF VESTIBULE PARTITIONS AND BLAST ENCLOSURE;
AND ALLOWS FOR WORK SURGE STORAGE AREAS BEFORE AND AFTER TREATMENT OF WORK.